N(4)-phenyl substituted semicarbazones and thiosemicarbazones (1-4) of propiophenone and 4’- methylacetophenone have been synthesized and characterized by spectrometrical methods analyses (IR, RMN 1H &13C, SM). All compounds were evaluated for their in vitro trypanosomal activity against the bloodstream form of the strain 427 of Trypanosomabruceibrucei and have been tested on larvaeofbrine shrimp, Artemiasalina LEACH, for their toxic activity. The selectivity index (SI) of each molecule was too designed. In the group, propiophenone 4- phenyl-3-thiosemicarbazone 4 has exhibited greater trypanocidal activity with a half-inhibitory concentration (IC50) value equal to 7.63 micromolar (μM). 4’-methylacetophenone 4-phenylsemicarbazone 1 showed moderate antitrypanosomal activity (IC50 = 62.54 μM). Other, 2 and 3, presented little or no activity against the parasite (IC50> 100 μM). Except propiophenone 4-phenylsemicarbazone 2 which offered a toxic activity on larvae given the halflethal concentration LC50 = 107.49 μM and SI = 0.518 < 1 and has then a good selectivity on cells of larval shrimp Artemiasalina, all compounds showed negligible toxicity (LC50> 281 μM and SI > 1, compounds 1, 3 and 4). They turn out quite selective on the parasite. Synthesized compounds could constitute a new class of anti-trypanosomal drug candidates.